P1634: EFFICACY AND SAFETY OF ELTROMBOPAG IN THE TREATMENT OF CHRONIC HEPATITIS B VIRUS INFECTION PATIENTS WITH THROMBOCYTOPENIA（HBV-TP）: A PROSPECTIVE, MULTI-CENTER, SINGLE ARM, PHASE II TRAIL
Authors: Y. Chen, Y. Huang, Y. Lai, J. Peng, Z. Zhou, H. Zhou, R. Zhou, R. Yang, L. Zhang
Journal: HemaSphere (2022)

Background: The standard treatment of chronic hepatitis B virus infection patients with thrombocytopenia (HBV-TP) is not well established. Long-term glucocorticoid therapy and rituximab therapy could probably activate hepatitis virus replication and aggravate the disease. Thrombopoietin-receptor agoinst such as eltrombopag shows good efficacy and safety profile in immune thrombocytopenia（ITP） without immunosuppression, while the data of eltrombopag in HBV-TP is limited. Aims: To evaluate the efficacy and safety of eltrombopag in the treatment of chronic hepatitis B virus infection patients with thrombocytopenia. Methods: This is a prospective multicenter single-arm Phase 2 study with two stages. Adult HBV-TP patients with baseline platelets count ＜30x109/L，who were not accompanied by decompensated manifestations such as cirrhosis and splenomegaly were eligible for recruitment. By the end of stage 1（week1-6）, patients who responded to eltrombopag could enter a 16-week prolonged stage (stage 2) to evaluate the long-term efficacy and safety. The initial daily dose of eltrombopag is 25 mg and could be adjusted to 75 mg as maximum to maintain platelet counts between 50 × 109/L and 150 × 109/L. Patients were assessed for platelet counts weekly in Stage1 and every 4 weeks in the Stage2. Response to treatment was defined as a platelet count of ≥ 50 × 109/L, and complete response was defined as platelet count ≥ 100 × 109/L. The primary endpoint is the proportion of responders at the end of week 6. Subgroup analysis was performed by disease duration (newly diagnosed (0-3 months), persistent (> 3-12 months), or chronic (> 12 months)). Results: By this data cut-off before December 31,2021, 43 patients were screened and 38 patients were recruited. Among them 18 patients were male and 20 were female, the median age was 47(20-67) years old and the median disease duration was 6.5(1-360) months. The median baseline platelet count was 16.5(3-29) × 109/L, with newly diagnosed group 14.5(8-27) × 109/L(n=6), persistent group 13(3-29) × 109/L(n=15), chronic group 19(4-27) × 109/L(n=17), respectively. The response rate and complete response rate was 70.3% and 37.8% at week 6 after eltrombopag treatment within 37 patients. The response rate and complete response rate in newly diagnosed group(n=6), persistent group(n=14), and chronic group(n=17) was 33.3% and 33.3%, 78.6% and 28.6%, 76.5% and 47.1%, respectively. The median duration of response in Stage 2 was 18(3-21) weeks (n=28). Treatment-related AEs were mainly of CTCAE grade 1 or 2 in intensity. There were two SAEs requiring additional medical intervention or discontinuation of eltrombopag. One had myocardial infarction during the experiment, while continued with eltrombopag and antiplatelet drugs after cardiac stent implantation to complete this study. One patient stopped taking elrombopag due to obvious liver laboratory abnormalities and lower extremity venous thrombosis. Summary/Conclusion: Eltrombopag is effective in chronic hepatitis B virus infection with thrombocytopenia, and adverse reactions are tolerable. It is necessary to monitor platelet counts and liver function during eltrombopag treatment to manage the risk of thrombosis.